IIRC soybean products (like tofu) are said to contain small amounts compounds with estrogen-like properties. Hence males consuming significant quantities of these products may be affected by higher than normal level of circulating estrogens.

I don't know how much tofu ingestion is required to produce a noticeable effect (such as gynecomastia), but I assume it would have to be a major dietary component. In Asian countries, soybean consumption is much higher than typical in the US, so perhaps more likely to be an issue there. Might be worth a literature search on the subject, but I haven't done that, so I don't know if it's been verified.